Where is the ozone decreasing in the ozone layer?

Mostly over Antarctica, and to a lesser extent over the North Pole.

Thanks to worldwide agreement and compliance with the 1987 UN Montreal Protocol (which agreed to phase out ozone depleting chemicals) global ozone depletion is no longer increasing. The Montreal Protocol is the most (some would say only) successful international agreement and scientists hope the ozone layer will have completely recovered by 2060.